“ Christina loves getting attention for looking trashy and not put together and uses Taylor as a kind of ‘anti-inspiration’ for her fashion, makeup and hair now," a source said.
"She can’t stand Taylor's preppy prissy ‘caged bird in a tower’ thing -- and has used her as a guide on what NOT to wear for over 18 months."
Country pop singer Swift, 24, is known for her classic look while the platinum blonde The Voice judge, 33, flaunts her sexuality every chance she gets.
But now that Aguilera and her boyfriend Matthew Rutler are expecting a baby (her second child), the "Beautiful" singer is outraged that Swift has recently adopted a slightly more sexy look, according to the source.
This month, Swift has showed off her legs in short shorts and a mini skirt and also tried a more daring red carpet look with a crop top at the recent ACM Awards.
"Christina is angry that Taylor is flaunting herself these days--while she herself is sporting a baby bump!" the source said.
"It’s strange to think of these two as rivals when they have vastly different fan bases, but it’s the feud is real and Taylor’s now getting her own back with Xtina holed up with a baby on the way.”